Tyre sizing...

Merlin · Post by **Merlin** » Mon Aug 27, 2007 9:56 am

Hi all,

We need to fit new tyres to the '66 as the low profiles are overrevving the engine...same problem on my bug, but that's not on the road atm.

We're going with 15" 195s.

Do we need a 60 or 65 profile?

Thanks, N.

brianj · Post by **brianj** » Mon Aug 27, 2007 11:13 am

http://www.miata.net/garage/tirecalc.html

Use this to decide if you want to change your tyres what the effect will be on the gearing . This shows why 195/80 is a good option on the bus with a warm motor.

Merlin · Post by **Merlin** » Mon Aug 27, 2007 11:26 am

Thanks Brian,

The closest to stock there is a 65 profile.

Am I doing any significant damage running an approx. 20 rev overrev? I would guess no?

Damn, those fat tyres are going to look wierd-ass and old-school on the bugs.

Oh kak...I just thought about something...this is going to seriously F' up my bug, which is lowered in front!

Are any of you running 195s, stockish profile, on lowered front beams?

Thanks, N.

Bossie · Post by **Bossie** » Mon Aug 27, 2007 1:23 pm

Oh kak...I just thought about something...this is going to seriously F' up my bug, which is lowered in front!

HEHEHE, this is confirmation of what FIG mentioned in another forum last week about lowering, can do if you want to, but more often than not guys are running into problems soon.

Mervin guess you can look at the white walls that Rui (Callooker) has a set left, at least it will solve the "looks"

issue...

Merlin · Post by **Merlin** » Mon Aug 27, 2007 1:45 pm

Spoken to two gurus sincce this post, and the best I can do is install and check...year-endish.

I refuse to run any white-walls based on past safety issues. Many brands have proven to rub their sidewalls to dangerous levels.

There's a lot of thought going into this car Bossie...it's not a backyard hack by any means.

N.

Bossie · Post by **Bossie** » Mon Aug 27, 2007 2:03 pm

There's a lot of thought going into this car Bossie...it's not a backyard hack by any means.

Sounds good, glad you mentioned the white walls aren't a good option, seems like most purists DEEG them White Walls!!!

Is your project on the forum - share some photos with the maaitjies!!!

Cheers,

vader · Post by **vader** » Mon Aug 27, 2007 8:48 pm

MTM be careful when putting ANY undersized tires on your bug. Here I speak from lots of experience.... 4 rebuilds, dropped valves, snapped con rods and cranks, they really don't like over reving

Unless you build it strong

We did discuss this at length some where.... But if you want to work out your tires sizes and you dont have the web handy..

195 r65 15 =
15'x2.54cm = 38.1
195 x 65% x 2=253.5
253.5+38.1= od 291.6cm

vader · Post by **vader** » Mon Aug 27, 2007 9:07 pm

Sorry couldn't find the thread....

Merlin · Post by **Merlin** » Tue Aug 28, 2007 8:27 am

My Beetle is in full swing Bossie, but seeing as how the last update on it secured little interest I've refrained from updating it since. Projects section somewhere... "The Bug Project".

My Mother's bug is slowly getting sorted.

The one front tyre on the '66 had two punctures, and a MAJOR gash on the inside wall of the other front tyre was found yesterday at the wheel shop. The dealer reckoned a blowout within a week!

What luck!

The '66 is now Home with new Yokohama 195/60 tyres, and it really looks awesome!

I have the option of Yokohamas or Michelins (more $) on my bug later this year, but the clearance issues with the drop are worrying me.

I've also got issues with the rear wheels sticking out even further than before...combination of discs and IRS.

I'm not keen on wide fenders, as it takes away the stock look, and causes issues with running boards, but I may be forced to go that route.

Tony, I used BrianJ's link and 60 profile with 195s is correct. It is within 0.5 tolerance, and equates to 0.3 km/h difference at 100 km/h.

The 40 profile came with my bug Tony. The Goodyear F1s are some of the best tyres I've ever driven with, but I can't get 195 F1s in a higher profile.

I'll be keeping those 4, plus the two 50 profile tyres that came off the '66 and when my bugs done, I'll be having a nice blowout/drifting weekend.

N.

Bossie · Post by **Bossie** » Tue Aug 28, 2007 9:45 am

...combination of discs and IRS.

OK, time for a bit of education PLZ!!! What is IRS, and what does it do for your VW? Scuse if it is an issue that has been deliberated at length, but I am from the other side of the Boerewors Curtain and new in this field!!

Blitzkrieg · Post by **Blitzkrieg** » Tue Aug 28, 2007 9:50 am

My Beetle is in full swing Bossie, but seeing as how the last update on it secured little interest I've refrained from updating it since. Projects section somewhere... "The Bug Project".

Come on Merlin!!Don't disappoint us now, give us an update

Merlin · Post by **Merlin** » Tue Aug 28, 2007 9:56 am

Google is your friend.

IRS refers to a 4-link suspension design that first appeared in '68, in different variations on select cars.

South Africa never got it.

It's based on the swingaxle design but utilizes an extra arm pivoted on the torsion tube, and at the hub.

It helps the suspension travel in a more upright manner rather than the well-known arc of a swingaxle.

It's primarily used on Hot VWs, as it's a lot more stable with performance.

I managed to source a donor IRS vehicle here at a crazy price, a rather special VWSA-sourced one at that.

I'm converting my LHD pan to IRS with some difficulty...not many people here have done it, so making jigs, etc. is an experimental process.

IRS helps make the car a bit more stable in crosswinds, over bumpy roads, etc. and will get you that extra handling performance at extreme levels.

As for the discs, my bug has been converted and runs GTi discs at the back, along with stock '67 discs up front.

N.

Aircooled VW South Africa

Tyre sizing...

Tyre sizing...

Tyres & Stuff.